Gemcheck — TCG Card Grader

About this app

Gemcheck measures your card's centering the way the grading houses measure it — before you pay to find out. Photograph the front and back. Gemcheck corrects the perspective, finds the cut edge and the printed frame, and measures the border widths in millimetres. Then it tells you what PSA, BGS and CGC each allow at every grade, and where your card falls. CENTERING, MEASURED • Left/right and top/bottom, front and back • Border widths in millimetres, from a perspective-corrected image • The highest grade each house's published centering tolerance allows CORNERS, AGAINST YOUR OWN CARD Every corner is compared to the die-cut arc that card was actually made to — fitted from all four of its own corners, not assumed from a constant. You get a score out of 1000 per corner, the arc drawn over the corner itself, and a mark on the worst point, so you can see where the number came from. SURFACE, IN RELIEF A relief view lights the card from one side. Flat card falls away to an even grey and what stands up is topography: a crease, a dent, a pushed corner, the weave of the stock. Slide it over the real image at any magnification. WHAT IT SELLS FOR Gemcheck Pro identifies your exact card from its artwork and shows what copies of it are actually listed for on eBay right now — graded PSA 10, graded PSA 9, and ungraded — with photographs and asking prices. The gap between the raw price and the slab price is the whole grading decision, and it is a number, not a feeling. WHAT IS NEVER PROMISED A grade. Graders allow themselves discretion over their own published tolerances, so even a measured ceiling is a ceiling on the rule — not a guarantee. Gemcheck will not pretend otherwise. ADJUST ANYTHING The cut edge and the printed frame sit on one screen over your original photograph. Pinch to zoom, drag any line, or nudge it a hundredth of a millimetre at a time. A loupe magnifies under your finger. Nothing is measured that you cannot see and correct yourself. YOUR BINDER A saved scan keeps its photographs and its geometry, so any card can be re-adjusted or re-shot later and re-measured through exactly the same code that measured it the first time. Track what you have sent for grading, and record what came back. MEASURED ON YOUR DEVICE Every measurement happens on your iPhone and the results stay there. No account, no sign-in, no analytics, no tracking. There is one exception and we would rather lead with it than bury it: if you open the market section, one picture of the card is sent once so the card can be identified — after that it is never sent again. Measuring a card never sends anything anywhere. GEMCHECK PRO Photographing a card is free. Gemcheck measures it and saves it to your binder, and the subscription is what reveals the figures — the centering ratios, the corner scores, the surface relief, the manual adjustment tools and what the card sells for. There is no free tier and no trial: you can watch the app work on your own card, and decide from there. — Gemcheck Pro is an auto-renewing subscription. There is no free trial. • Weekly — $7.99 per week • Monthly — $14.99 per month • Yearly — $49.99 per year Prices are US dollars; your own currency is shown on the purchase screen before anything is charged. Payment is charged to your Apple ID at confirmation of purchase. Subscriptions renew automatically unless cancelled at least 24 hours before the end of the current period. Manage or cancel in Settings > Apple ID > Subscriptions. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ — Gemcheck is not affiliated with, endorsed by, or sponsored by Professional Sports Authenticator (PSA), Beckett Grading Services (BGS), Certified Guaranty Company (CGC), eBay Inc., or The Pokémon Company. Grading tolerances are taken from each company's own published standards.

You can photograph a card without subscribing now. Shoot the front and back, and Gemcheck measures and saves the card as usual. The subscription is what reveals its centering figures and the rest of the tools — so you can see the app work on your own card before deciding. The upgrade screen now shows real screenshots of the app rather than an illustration.

Momentum comes from crawler snapshots for the tracked storefront. “Viral growth signal” means unusually fast recent rating gains; it is an indicator, not download data.

1. First observed Sep 8, 2026 · 3:42 PM Free